Yemenia plane may have been circuiting

The Yemenia Airbus 310 that crashed into the Indian Ocean near Comoros may have been attempting a circuiting manoeuvre when it hit the sea, a pilots association says.

International Federation of Air Line Pilots Association, a group of over 100,000 pilots, made the claim in its daily newsletter late yesterday. It did not give a source for this information, but it is a well-respected industry group whose members are very familiar with airports around the world.

The plane, which crashed in poor weather and high winds, was carrying 153 people from France to Comoros via Yemen. One teenage girl has survived, but there is no word yet on other survivors.

The 2,900-meter (9,558-feet) long runway at Prince Said Ibrahim International Airport on Moroni island is adequate for modern airliners. But the airport is considered a difficult one for pilots due to prevailing weather conditions and hills to the east of the runway. Some airlines provide special training to pilots who need to fly in there.

"The field in question is thought of as being challenging, and certain operators consider it a daytime-only airport," said Gideon Ewers of the London-based pilots' association.

The Yemenia plane was trying to land in the dark, about 1:30 in the morning, amid bad weather.

For planes coming in from the south, the Moroni runway is equipped with an all-weather instrument landing system, but landings from the north are performed visually.

The all-weather Instrument Landing System (ILS) provides precision guidance for pilots on their final approach by projecting an electronic beam known as the "glide path" which guides airliners in to just above the runway threshold. This is projected on the control panel, which shows whether the plane is on the correct heading and altitude for touchdown.

Yesterday's accident occurred several kilometers (miles) north of Moroni airport, indicating that the crew — which would likely have opted for an ILS approach from the south in poor weather conditions — was probably following the path prescribed by the airport's chart for a go-around following a missed approach.

While the causes of this particular accident remain unclear, crashes while a plane is landing are often caused by unfavorable weather conditions, including wind shear.

Another frequent landing crash cause is "controlled flight into terrain" — in which an otherwise airworthy plane is accidentally flown into the ground or the water, usually because of the pilots' spatial disorientation.

Immediately after yesterday's crash, questions also arose about the extent of radar coverage at the Moroni airport, with some aviation experts wondering if deficiencies in the radar may have contributed to the accident.

Mohammed Moqbel, a Yemeni pilot who has flown to the Comoros, said the final approach at Moroni can be difficult because of the geography, weather and the airport's older radar.

"The airport is also very poor in terms of equipment ... they don't have advanced radar to guide planes," he said.

But many commercial and general aviation airports around the world that don't have heavy traffic are not equipped with radar or have very old radar equipment. Instead, they rely on a set of approved procedures and on other instruments to enable planes to land safely.

Although airports in the developed world usually have their own radar, these are generally used for managing air traffic en route or placing planes in holding patterns — rather than for guiding aircraft in for the landing itself.

"It's perfectly safe to carry out a visual approach, provided the meteo-conditions are good enough," Ewers said.